At the present time, one group of people who frequently encounter dogs in the course of their work are postmen. Dogs are commonly kept as household pets. Whilst many dogs can be good natured with their owners and people they are familiar with, they can be extremely aggressive to strangers. Also, many dogs have a strong territorial instinct, which again leads them to be extremely aggressive to strangers.
As a result, many postmen are attacked by dogs as they attempt to deliver mail. Postmen have adopted a variety of measures to counter this problem. One technique is to carry a conventional umbrella. The umbrella is opened in the face of a charging or aggressive dog. The sudden opening of the umbrella will in some cases startle the dog away. However, in many cases it is ineffective. The umbrella does not make any significant noise to assist in startling the dog. Also, conventional umbrellas are usually made of a fairly dark material, which again does not assist in startling the dog. If the dog is not deterred by the umbrella, then conventional umbrella structures are far too lightweight to resist damage by a determined dog. The cover material is light and easily torn, and the supporting rib structure cannot withstand the sort of loads applied by a medium or large size dog.
Further, many conventional umbrellas have a pointed end to the shaft. This can injure a dog. As most dogs are kept as domestic pets, it is desirable that any method of deterring attacks by a dog should not injure the dog.
What is required is an animal shield, which is lightweight, compact and easily carried. It should be capable of quick and easy deployment. Further, it should be capable of withstanding the loads or forces applied by dogs or other animals of concern.
Further, it is to be borne in mind that dogs are colour-blind. The vision of dogs and other animals is much more sensitive to light than humans, and this effect should be utilized.
Also, policemen, penitentiary guards and the like sometimes encounter hostile situations, where missiles, such as rocks, bottles, etc. are thrown at them. It is desirable to have available a shield which can be collapsed to a compact portable configuration, but which can be readily deployed.